The "jcifs.smb.SmbFileOutputStream.isOpen()Z" in the logs matches a defect, probably with the BSA application server upgrade, where an older version of a jar file is left in place in the <APPSERVER_INSTALL_DIR>\NSH\br\stdlib directory and causes a conflict.
We need to get an external KB article out there on this issue but try the following workaround from the current internal/draft article we have (KA404293):
1. Login to appserver machine
2. cd to <APPSERVER_INSTALL_DIR>\NSH\br\stdlib
3. List all files and see if there is multiple jcifs-<VERSION>.jar
continue with the next steps if you have found multiple jcifs-<VERSION>.jar:
4. Stop the appserver
5. rename older jcifs-<VERSION>.jar and move it from stdlib directory
6 Start the appserver and try installing agent again.
The files might be called jcifs-1.2.9 and jcifs-1.3.1. In that case, you would rename and move jcifs-1.2.9
Let us know how this goes and we'll work on getting the KA article tidied up and published if it fixes the issue for you.
Thanks man, this solved it.